To identify the hardware platform or software image information associated with a feature, use the Feature Navigator on Cisco.com to search for information about the feature or refer to the software release notes for a specific release. For more information, see the "Identifying Supported Platforms" section in the "Using Cisco IOS Software" chapter in this book.

LFI for Frame Relay and ATM VCs Configuration Task List

To configure the LFI for Frame Relay and ATM VCs feature, perform the tasks described in the following sections. The tasks in the two sections are required; the task in the remaining section is optional.

Configuring LFI Using MLP over ATM

LFI using MLP can be configured over ATM using a virtual template interface or a dialer interface. To configure LFI using MLP over ATM using a virtual template interface or dialer interface, perform the tasks in either the first two or the second two sections:

Configuring LFI Using MLP on a Virtual Template Interface

To configure LFI using MLP on a virtual template interface, use the following commands beginning in global configuration mode:

Command

Purpose

Step 1

Router(config)# interface virtual-templatenumber

Creates a virtual template and enters interface configuration mode.

Step 2

Router(config-if)#bandwidth kilobits

Sets the bandwidth value for an interface.

Step 3

Router(config-if)#service-policy output policy-name

Attaches the specified policy map to the output interface.

Step 4

Router(config-if)# ppp multilink

Enables MLP on the interface.

Step 5

Router(config-if)#ppp multilink fragment-delaymilliseconds

Configures the maximum delay allowed for transmission of a packet fragment on an MLP bundle.

Step 6

Router(config-if)#ppp multilink interleave

Enables interleaving of Real-Time Protocol (RTP) packets among the fragments of larger packets on an MLP bundle.

The ideal fragment size for MLP over ATM should allow the fragments to fit into an exact multiple of ATM cells. The fragment size for MLP over ATM can be calculated using the following formula:

fragment size = 48 x number of cells - 10

Fragment size at the MLP bundle can be configured using the following formula:

fragment size = bandwidth x fragment-delay/8

Note To attach a service policy to a multilink ppp bundle configured through a virtual template, make sure that the multilink ppp bundle interface is operational. If the interface is not operational, attaching the service policy fails. If a multilink ppp bundle interface is configured through a virtual template, at least two virtual access interfaces are configured, (that is, virtual-access 1 and virtual-access 2). One of these virtual access interfaces is a ppp interface and the other is a multilink ppp bundle interface.

When a service policy is attached to a virtual template, the error message "Class Based Weighted Fair Queuing not supported on interface virtual-access1" appears if the virtual-access1 interface is the ppp interface. Since the service policy is successfully attached to the multilink ppp bundle interface, this is not an error condition. To verify whether the service policy is attached correctly, use the show interfaces command and review the queuing policy.

Associating the Virtual Template Interface with an ATM PVC

To associate the virtual template interface with an ATM PVC, use the following commands beginning in global configuration mode:

(Optional) Creates a pool of dialup routers that all appear to be the same host when authenticating with CHAP.

Step 9

Router(config-if)# ppp chap passwordsecret

(Optional) Enables a router calling a collection of routers that do not support this command (such as routers running older Cisco IOS software images) to configure a common CHAP secret password to use in response to challenges from an unknown peer.

Step 10

Router(config-if)# ppp multilink

Enables MLP on the interface.

Step 11

Router(config-if)#ppp multilink fragment-delaymilliseconds

Configures the maximum delay allowed for transmission of a packet fragment on an MLP bundle.

Step 12

Router(config-if)#ppp multilink interleave

Enables interleaving of RTP packets among the fragments of larger packets on an MLP bundle.

Associating the Dialer Interface with an ATM PVC

To associate a dialer interface with an ATM PVC, use the following commands beginning in global configuration mode: